JMW said:
"Same as the costs of special steels batteries etc has to go into EV evaluations.
They are not zero emissions on an ashes to ashes accounting. Though the figures are disputed the early Prius came 60th in a list of lifetime pollutants and near the top came some kind of 4x4.... standard steels and they run a couple of times round the clock before they die and often as not they are kept running.
Battery disposal is also an issue."
Embodied energy is trotted out often in this sort of discussion to "prove" one thing is more virtuous than the other. Unless the auto manufacturers are paying a great deal less for their energy than I'm paying for mine, given the prices being charged for the vehicles, simple economics indicates that there's no way that the embodied energy in a vehicle comes close to the amount of energy it consumes during its lifetime.
The Prius has only 20 kg of nickel in its batteries. True, there's more energy in making a kg of nickel than in making a kg of steel, but probably not by more than an order of magnitude- say about the same as the cost of an extra 200 kg of steel. That's roughly the weight difference between most SUVs and the Prius, i.e. the embodied energy of the batteries is moot.
Battery disposal for the Prius is also no problem, as nickel metal hydride batteries are very different in the toxicology department when compared to nickel cadmium batteries or even the ubiquitous lead/acid batteries. Recovering the nickel from these batteries is far easier than recovering it from the ore. Lithium ion batteries are not used in the Prius, but are also not a particular toxicological problem. Lithium supply might be a problem once we have millions of EVs, but that's more a price issue than anything else.
So yes, "the figures are disputed" in that study.
What's put in and what's taken out of the analysis and what assumptions are made can entirely determine the outcome of studies like this. What I'd like to see instead is a carbon tax at the source on all the fuels, regardless whether those fuels are used to make electricity or car parts or to drive the vehicles themselves. Then all you'd need to know is the purchase price and some estimate of what your fuel and maintenance costs will be to determine what makes the most sense to buy.